Signal cycling device



p 1958 J. P. ECKERT, JR.. ETAL 2,854,574

SIGNAL CYCLING DEVICE Original Filed April 13. 1950 Fig.1

INPUT CLEAR NORMAL OUTPUT- ig.2b

TlME- 1 mos-40 SIGNAL CYCLING DEVICE John Presper Eckert, Jr.,Philadelphia, Pa., and Albert A.

Auerbach, Levittown, N. 1., assignors, by mesne assignments, to SperryRand Corporation, New York, N. Y., a corporation of Delaware Originalapplication April 13, 1950, Serial No. 155,628, new Patent No.2,687,473, dated August 24, 1954. Divided and this application July 6,1954, Serial No. 441,298

6 (Ilaims. (Cl. 25027) This invention relates to a pulse formingapparatus and more particularly to an apparatus driving an electricaldelay line developing a rectangular impulse of a predetermined width inresponse to an input signal.

This application is a division of our copending application, Serial No.155,628, now Patent No. 2,687,473, granted August 24, 1954, filed April13, 1950.

The invention described in the aforementioned application provides forthe circulation of a signal impulse in a signal loop comprising a delayline, a pulse forming regenerator and a timing gate, so that once asignal impulse enters the signal loop it continues to circulate thereinuntil the loop is cleared. When used for selective gating or selectivesequential activation, it was shown that it was only necessary toutilize a single, preferably rectangular, impulse.

Accordingly, objects of this invention are:

To provide a rectangular impulse of a predetermined width to anelectrical delay line in response to an input signal.

To provide a rectangular impulse to an electrical delay lineirrespective of the signal configuration of the input thereto.

To provide a rectangular impulse to an electrical delay line from anelectric valve.

T o insure that the output from an electric delay line driver will be arectangular impulse.

Other objects of the invention will in part be described and in part beobvious as the following specification is read in conjunction with thedrawings in which:

Figure 1 illustrates schematically a circuit embodying the invention,and

Figure 2a-c illustrates voltage-time waveforms characterizing theinvention.

Referring now to the drawings which illustrate a particular embodimentof this invention, typical values of potential are given for purposes ofillustration only and not in order to limit the scope of the invention.Positive voltage sources are identified by even numbers and negativevoltage sources are identified by odd numbers. Figure 1 shows anelectrical delay or transmission line 19 and a driver valve 149associated therewith. Valve 149 is normally nonconducting having itscontrol grid 150 connected to a negative bias potential of 21 volts bymeans of a grid resistor 151, which has a restoring diode 152 connectedin parallel with its anode linked to the said negative potential of 21volts. The cathode 153 of delay line driver valve 149 and the suppressorgrid 154 of the said valve are connected together and to groundpotential; the screen grid 155 is bypassed to ground by a capacitor 156and is connected to a control switch 102 which contacts either a normalterminal 158 bearing a positive potential of 120 volts or a clearterminal 159 bearing a negative clearing potential of minus 11 volts.The anode 160 of valve 149 is linked to a positive clamping potential bya clamping diode 161 which has its anode connected to a positivepotential source having a voltage determined by later reviewedconsiderations, and is nited States Patent D ICQ also connected to apositive potential of 240 volts through a parallel inductor-resistorcombination 162, the delay line 19 and anode resistor 165. Delay line 19is composed of a plurality of mutually coupled series connectedinductors 163 connected at their junction to capacitors 164; all thecapacitors 164 have one plate returned to a positive potential of volts.The said delay line 19 is provided with a series of tap connections 104to 109 inclusive along its length for the delivery of signals toapparatus as described and claimed in the aforementioned application.

The junction point of the delay line 19 and the anode resistor 165, isjoined to a pair of parallel connected diode resistor branches 113 byconnecting to the anode of the normally conducting diode 166 and thecathode of the normally nonconducting diode 170. Diodes 166 and 170 arerespectively series connected to a load resistor 167 and a load resistor171 connecting to a junction point which is returned toa positivepotential of volts through a voltage divider resistor 169 and to apotential of 90 volts through a voltage divider resistor 168, andby-passed to ground potential through a humfiltering capacitor 114. Thisarrangement is utilized to terminate delay line 19 with itscharacteristic impedance and so prevent signal reflection into delayline 19, since it is assumed that the impedance of anode resistor willbe higher than the characteristic impedance of delay line 19.

In operation, the delay line driver valve 149 has its control grid 150maintained, by means of the restorer diode 152, at a potential whichcannot become more negative than a potential of minus 21 volts, so thatwhen a positive impulse of suflicient magnitude is transmitted theretovia terminal in Figure 1, by apparatus not shown, the said valve 149will, in response, normally become conductive. When the control switch102 is placed in the clear position, control grid 150 is held belowcutoii and the delay line driver valve 149 does not become conductive inresponse to positive signals upon its control grid 150, therebypreventing the transmission-of signals to the delay line 19. Theparallel inductor-resistor combination 162 prevents ringing oroscillations in the anode circuit of said delay line driver valve 149,allowing a signal of substantially rectangular wave form to appear inthis circuit in response to a positive impulse on the control grid 150.a

The anode voltage excursion of the driver valve 149 is limited to thelower level of 90 volts by the normally nonconducting clamping diode 161and to an upper level dependent upon the voltage drop through the anoderesistor 165. In the foregoing discussion, the connection of theclamping diode161 between the anode 160 of the valve 149, and apotential of approximately 90 volts has been mentioned. The purpose ofthis clamp is to shorten the time between the arrival of apositive-going impulse at the control grid 150 of the valve 149 and thedevelopment of the maximum negative-going excursion at the anode 160. Aconsideration of the diagrams in Figure 2a, b and c will make clear therequirement for the diode 161 and the manner of selecting the potentialto which it is returned.

Referring now to Figure 2a, it is assumed that a positive-going impulseis applied to the control grid 150 at a time 200. The resulting anodecurrent surge, taken in conjunction with the surge impedance of the line19, produces an immediate voltage change indicated by the negative-goingstroke 201 across the delay line 19. The anode current continues toflow, however, and as it is propagated down the delay line, passessuccessively through section after section thereof. Each of thesesections has an appreciable resistance, and as the current traversesadditional sections, the anode 160 becomes progressively more negativeby the amount of the additional drop contributed,

"as indicated by the section 202 of the voltage-time characteristic inFigure 2a.

At the time 205, the control electrode 150 returns to cut-oft potential,interrupting the fiow of anode current, permitting the anode potentialto return to its rest value along the postiive-going stroke 203.

Inspection of the Figure 2a reveals that the negative excursionof'theanode 160 continues during the presence .required'for the signalto attain its final value is greatly reduced, through the elimination ofthe sloping stroke 202. To. perform this function, the diode 161 isprovided, ;and.returned to a potential which must be at least aspositive as the remainder after the subtraction of the initial surgefrom the anode rest potential. The initial surge magnitude is, ofcourse, determined by measurementor multiplying the anode current surgeby the line surge impedance. A less positive clamping potential wouldpermit a portion of the sloping stroke 202 to get through the circuits.A more positive clamping potential willdo no harm to the general form ofthe impulses, but merely reduce the peak amplitude available. Thevoltage excursion of anode 160 of valve 149 which is also the voltagewave available from any of the taps 104 to 109 on delay line 19 isobtained as in Figure 2c.

The said negative impulse traverses the delay line 19 which interposes adelay of the magnitude desired. Upon reaching the load end of the delayline 19, the negative impulse is impressed on the two parallel connecteddiode resistor branches 113, resulting in the nonconduction of normallyconducting diode 166 and the conduction of diode 170 which transmits anegative impulse via the terminal 191 in-Figure 1 to apparatus, notshown, Where the negative pulse may be retimed, amplified and reformedand applied as the positive impulse to the grid 150 of valve 149 asdescribed and claimed in the aforementioned application.

While this invention has been described and illustrated with referenceto a specific embodiment, it is to be understood that theinvention iscapable of various modifications and applications, not departingessentially from the spirit thereof, which will become apparent to thoseskilled in the art.

What is claimed is:

'1. In combination, an electric delay line connected at one end with aconductor having a first potential, an electric valve connected betweenthe other end of said delay line and a conductor having a secondpotential, and a diode connected between the electric valve end of saiddelay line and a conductor having a reference potential intermediatesaid first and second potentials.

2. In combination, an electric delay line connected at one end with aconductor having a first potential, an electric valve connectedbetweenthe other end of said delay line and a conductor having a secondpotential, said valve havingthe property of passing a current surge ofpredetermined magnitude in response to the application of signal stimulithereto, and a diode connected between the electric valve end of saiddelay line and a conductor having a potential not less than thediiference between said first potential and the product of the surgeimpedance of said delay line by the magnitude of said current surge.

3. In combination, an electric driver tube having anode, cathode andgrid electrodes, a source of anode supply potential for'said drivertube, an electric delay line connecting said source of potential to theanode of said tube, and a clamping circuit connected to the junction ofsaid delay line and said anode including a source of reference voltageand a unilateral conductor connected in series, said reference voltagehaving a potential lower than said anode potential.

4. In combination, a delay line, an electric valve, the output of whichis connected to the input of said delay line, means for preventingoscillation in the output circuit of said valve interposed between saidvalve and said delay line, a clamping device connected to the junctionof said valve and of said means for preventing oscillation, a voltagesource connected to the output end of said delay line, an impedanceinterposed between said output end of said delay line and said voltagesource, and means for terminating said-delay line connected to thejunction of said impedance and of said delay line.

5. The combination according to claim 4 wherein said means forpreventing oscillation comprise an inductor and resistor arranged inparallel.

6. The combination according to claim 4 wherein said clamping devicecomprises an asymmetrical conductor and a voltage source.

References Cited in the file of this patent UNITED STATES PATENTS2,266,401 Reeves Dec. 16, 1941 2,299,571 Dome Oct. 20, 1942 2,521,952"Stephenson Sept. 12, 1950 2,632,847 Reed Mar. 24, 1953

